Diffusivity of various polyvalent elements in a Na2O·2SiO2 glass melt

Diffusion coefficients of various polyvalent ions (Sn2+, As3+, As5+, Sb3+, Sn2+, V4+, V5+, Cr3+, Cr6+, Fe3+, Cu+) were measured in a Na2O·2SiO2 glass melt with the aid of square-wave voltammetry. Within the temperature range from 850°C to 1550°C, a linear correlation between log D and 1/T was observed. At the same temperature, diffusion coefficients varied by up to the factor of 2800. Polyvalent elements showing two redox steps (As, V, Cr) always possess higher diffusion coefficients in the lower valence state. The diffusion coefficients measured correlate with those reported for a soda–lime-silicate melt.